What is a common chemical used for water disinfection?

Chlorine is a widely used chemical for water disinfection due to its effectiveness in killing a broad spectrum of pathogens, including bacteria, viruses, and protozoa. It can be introduced into water systems in several forms, such as chlorine gas, sodium hypochlorite, or calcium hypochlorite. This versatility allows water treatment facilities to maintain desired levels of disinfection, ensuring that water remains safe and potable during distribution.

When added to water, chlorine reacts to form hypochlorous acid, which is a strong oxidizing agent that disrupts the cellular processes of microorganisms. Chlorination not only disinfects but also helps to maintain a residual concentration of the disinfectant in distribution systems, which provides ongoing protection against potential recontamination.

In contrast, options like fluoride, sodium bicarbonate, and calcium carbonate are not primarily used for disinfection. Fluoride is added to drinking water for dental health benefits, sodium bicarbonate is often used to adjust pH levels, and calcium carbonate serves mainly as a hardness contributor that can help stabilize pipe systems but does not have disinfectant properties.